USN-222-1 fixed a vulnerability in the Perl interpreter. It wasdiscovered that the version of USN-222-1 was not sufficient to handleall possible cases of malformed input that could lead to arbitrarycode execution, so another update is necessary.

Original advisory:

Jack Louis of Dyad Security discovered that Perl did not sufficiently check the explicit length argument in format strings. Specially crafted format strings with overly large length arguments led to a crash of the Perl interpreter or even to execution of arbitrary attacker-defined code with the privileges of the user running the Perl program.

However, this attack was only possible in insecure Perl programs which use variables with user-defined values in string interpolations without checking their validity.